During the mid-luteal phase of the menstrual cycle, there are two modulations of LH pulses; i.e., in addition to the tall amplitude pulses, LH pulses of small amplitude are observed. This protocol will test (1) whether these small amplitude pulses are biologically active and (2) whether their amplitude will increase with blockade of ovarian steroid secretion by ketoconazole. During the mid-luteal phase of the menstrual cycle, LH pulses of both small and exceedingly large amplitude are noted. The objective of this study was to test whether small amplitude LH pulses are biologically active and whether the amplitude of such pulses increases with blockade of ovarian steroid secretion by ketoconazole.